| 摘要 |
This specification discloses a caster in which a roller is rotatably mounted on an axis disposed at 45 DEG to the vertical with the upper portion of the roller being rotatably received in a downwardly opening housing and provided with an outwardly extending flange in the zone of overlapping portions of the roller and housing to exclude foreign matter from the latter and maintain frictional resistance to rotation at a minimum. The bottom wall of the roller is integrally joined to the cylindrical wall thereof by a bevelled or rounded structure that includes an annular groove extending upwardly with the groove defining a flexible rolling wall that will give under pressure. The bottom together with the inner wall of the groove are supported by a spider comprising six webs that are integrally joined to a central hub member, the bottom, and grooved wall structure aforesaid.
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